This invention relates in general to fluid control valve assemblies for high-pressure fluid circuits such as vehicle brake systems, and in particular to high-pressure fluid control valve assemblies having a microvalve device attached via a high-pressure fluid connection to a fluid distributing substrate.
MicroElectroMechanical Systems (MEMS) is a class of systems that are physically small, having features with sizes in the micrometer range. These systems have both electrical and mechanical components. The term xe2x80x9cmicromachiningxe2x80x9d is commonly understood to mean the production of three-dimensional structures and moving parts of MEMS devices. MEMS originally used modified integrated circuit (computer chip) fabrication techniques (such as chemical etching) and materials (such as silicon semiconductor material) to micromachine these very small mechanical devices. Today there are many more micromachining techniques and materials available. The term xe2x80x9cmicrovalve devicexe2x80x9d as used in this application means a complete, functioning valve having features with sizes in the micrometer range, and thus is by definition at least partially formed by micromachining. Furthermore, a xe2x80x9cmicrovalve devicexe2x80x9d, as used in this application includes a microvalve, and may include other components such as pressure, temperature, flow or other types of sensors, pumps or other valves of various types. It should be noted that if components other than a microvalve are included in the microvalve device, these other components may be micromachined components or standard sized (larger) components.
Various microvalve devices have been proposed for controlling fluid flow within a fluid circuit. A typical microvalve device includes a displaceable member or valve movably supported by a body. Depending on the type of valve, the valve may be operatively coupled to an actuator for movement between a closed position and a fully open position. When placed in the closed position, the valve blocks or closes a first fluid port that is placed in fluid communication with a second fluid port, thereby preventing fluid from flowing between the fluid ports. When the valve moves from the closed position to the fully open position, fluid is increasingly allowed to flow between the fluid ports.
The invention relates to a fluid control valve assembly including a microvalve for controlling fluid flow in a fluid circuit having a relatively high fluid pressure requirement, such as vehicular brake system, is fixed to an associated fluid distributing substrate with a high-pressure fluid connection. The fluid distributing substrate is provided with fluid passages adapted for connection to a fluid source to provide communication between the fluid source and the microvalve device. The connection between the microvalve and the fluid distributing substrate may include metallic connections forming electrical current paths between the microvalve and the substrate; solder joints forming part of the pressure boundary of the high-pressure fluid connection; underfill formed of elastomeric or other adhesive; and bonding between the substrate and the microvalves in only selected portions of the surface of the microvalve.
Various other objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings.